final htmlRegExp = RegExp(
  r'^<([a-z]+)([^<]+)*(?:>(.*)<\/\1>|\s+\/>)$',
  multiLine: true,
  caseSensitive: false,
);
bool isHtml(String html) {
  var result = htmlRegExp.hasMatch(html);
  if (result) return true;
  return isHTML(html);
}

bool isHTML(String str) {
  final RegExp htmlRegExp =
      RegExp(r'<[^>]*>', multiLine: true, caseSensitive: false);
  return htmlRegExp.hasMatch(str);
}
